Transform addresses to postcode

I have a dataset with c150k UK addresses and I need to obtain geographical coordinates and/or postcode based on the street addresses provided. The addresses provided do not have postcode. This project is for someone who has expertise in GIS, API. The person has to provide the code used to extract data. The nominatim API can be used to run the search or any other API https://nominatim.openstreetmap.org/ui/about.html